The advisories, published plainly
The discover-scuba session carries two standing advisories — not recommended for pregnant travelers or travelers with poor cardiovascular health — plus an operator note advising against participation under the influence of alcohol. The two full-day routes repeat the pregnancy and heart advisories and add spinal injuries to the list. None of this is boilerplate: the scuba session puts you under water, and the full-day routes put you at the top of a volcanic crater and in long coach stretches.
Treat the advisories as the operator's screening tool, not a suggestion to self-assess optimistically. If any line applies to you or a travel companion, the honest move is to message the operator before booking — describe the condition, ask what they advise, and let their answer decide the booking. The sea adds its own screening: sessions and boat days answer to conditions, and the checked listings' 24-hour cancellation windows are the clean exit.
Plan the week, not just the day
Health checks interact with the rest of an island trip. A red-eye arrival, a hangover from Jeju City's bars, or a knee already tired from the crater climb each change what the water will forgive. Schedule the scuba session after a rested night, keep the morning before it unbooked, and if your group mixes divers and non-swimmers, the full-day haenyeo routes keep everyone together on shore while the scuba session runs separately.
For choosing between the formats once health is settled, start from the water-day comparison.
Common questions
Can pregnant travelers join the full-day routes?
The checked listings advise against it for both full-day days as well as the scuba session. Confirm any exceptions directly with the operator before booking.
Is a doctor's certificate required?
None of the checked listings states a certificate requirement at booking. That can change per operator and season, so ask in writing when you book, especially for the scuba session.